drm/amd/display: Add mode validation and CEC tests for connector

Add KUnit coverage for connector mode validation and HDMI CEC:
mode_valid rejects interlaced and doublescan modes, set_edid with no
notifier, and the S3 suspend/resume CEC handlers.

Assisted-by: Copilot:Claude-Opus-4.8
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 108 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
index 01352fc9445e..0b97fbaf8f5a 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
@@ -356,6 +356,7 @@ void amdgpu_dm_hdmi_cec_set_edid(struct amdgpu_dm_connector *aconnector)
 	cec_notifier_set_phys_addr(n,
 				   connector->display_info.source_physical_address);
 }
+EXPORT_IF_KUNIT(amdgpu_dm_hdmi_cec_set_edid);
 
 void amdgpu_dm_s3_handle_hdmi_cec(struct drm_device *ddev, bool suspend)
 {
@@ -376,6 +377,7 @@ void amdgpu_dm_s3_handle_hdmi_cec(struct drm_device *ddev, bool suspend)
 	}
 	drm_connector_list_iter_end(&conn_iter);
 }
+EXPORT_IF_KUNIT(amdgpu_dm_s3_handle_hdmi_cec);
 
 
 struct drm_connector *
@@ -2327,6 +2329,7 @@ fail:
 	/* TODO: error handling*/
 	return result;
 }
+EXPORT_IF_KUNIT(amdgpu_dm_connector_mode_valid);
 
 int amdgpu_dm_fill_hdr_info_packet(const struct drm_connector_state *state,
 				   struct dc_info_packet *out)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
index c56efbc1f26b..ee20f2c2a80b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
@@ -4900,6 +4900,103 @@ static void dm_test_parse_displayid_vrr_sets_range(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, connector->display_info.monitor_range.max_vfreq, 144);
 }
 
+/**
+ * dm_test_mode_valid_interlace_rejected - Test interlaced modes are rejected
+ * @test: The KUnit test context
+ *
+ * Interlaced modes are rejected up front with MODE_ERROR before any sink or
+ * stream validation is attempted.
+ */
+static void dm_test_mode_valid_interlace_rejected(struct kunit *test)
+{
+	struct amdgpu_dm_connector *aconnector;
+	struct drm_display_mode *mode;
+
+	aconnector = kunit_kzalloc(test, sizeof(*aconnector), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, aconnector);
+	mode = kunit_kzalloc(test, sizeof(*mode), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, mode);
+
+	mode->flags = DRM_MODE_FLAG_INTERLACE;
+
+	KUNIT_EXPECT_EQ(test,
+			amdgpu_dm_connector_mode_valid(&aconnector->base, mode),
+			MODE_ERROR);
+}
+
+/**
+ * dm_test_mode_valid_dblscan_rejected - Test doublescan modes are rejected
+ * @test: The KUnit test context
+ *
+ * Doublescan modes are rejected up front with MODE_ERROR.
+ */
+static void dm_test_mode_valid_dblscan_rejected(struct kunit *test)
+{
+	struct amdgpu_dm_connector *aconnector;
+	struct drm_display_mode *mode;
+
+	aconnector = kunit_kzalloc(test, sizeof(*aconnector), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, aconnector);
+	mode = kunit_kzalloc(test, sizeof(*mode), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, mode);
+
+	mode->flags = DRM_MODE_FLAG_DBLSCAN;
+
+	KUNIT_EXPECT_EQ(test,
+			amdgpu_dm_connector_mode_valid(&aconnector->base, mode),
+			MODE_ERROR);
+}
+
+/**
+ * dm_test_hdmi_cec_set_edid_no_notifier - Test the no-notifier no-op path
+ * @test: The KUnit test context
+ *
+ * With aconnector->notifier NULL the function returns early and must not crash.
+ */
+static void dm_test_hdmi_cec_set_edid_no_notifier(struct kunit *test)
+{
+	struct amdgpu_dm_connector *aconnector;
+
+	aconnector = kunit_kzalloc(test, sizeof(*aconnector), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, aconnector);
+
+	amdgpu_dm_hdmi_cec_set_edid(aconnector);
+}
+
+/**
+ * dm_test_s3_handle_hdmi_cec_suspend - Test the suspend pass over connectors
+ * @test: The KUnit test context
+ *
+ * Suspend iterates all connectors, skipping writeback ones and calling the
+ * unset path on the rest; with NULL notifiers this is a crash-free no-op.
+ */
+static void dm_test_s3_handle_hdmi_cec_suspend(struct kunit *test)
+{
+	struct drm_device *drm = dm_test_alloc_drm(test);
+
+	dm_test_add_connector(test, drm, DRM_MODE_CONNECTOR_WRITEBACK);
+	dm_test_add_connector(test, drm, DRM_MODE_CONNECTOR_HDMIA);
+
+	amdgpu_dm_s3_handle_hdmi_cec(drm, true);
+}
+
+/**
+ * dm_test_s3_handle_hdmi_cec_resume - Test the resume pass over connectors
+ * @test: The KUnit test context
+ *
+ * Resume iterates all connectors, skipping writeback ones and calling the set
+ * path on the rest; with NULL notifiers this is a crash-free no-op.
+ */
+static void dm_test_s3_handle_hdmi_cec_resume(struct kunit *test)
+{
+	struct drm_device *drm = dm_test_alloc_drm(test);
+
+	dm_test_add_connector(test, drm, DRM_MODE_CONNECTOR_WRITEBACK);
+	dm_test_add_connector(test, drm, DRM_MODE_CONNECTOR_HDMIA);
+
+	amdgpu_dm_s3_handle_hdmi_cec(drm, false);
+}
+
 static struct kunit_case amdgpu_dm_connector_tests[] = {
 	/* get_subconnector_type */
 	KUNIT_CASE(dm_test_subconnector_type_none),
@@ -5166,6 +5263,14 @@ static struct kunit_case amdgpu_dm_connector_tests[] = {
 	KUNIT_CASE(dm_test_parse_displayid_vrr_null_edid),
 	KUNIT_CASE(dm_test_parse_displayid_vrr_no_displayid),
 	KUNIT_CASE(dm_test_parse_displayid_vrr_sets_range),
+	/* amdgpu_dm_connector_mode_valid */
+	KUNIT_CASE(dm_test_mode_valid_interlace_rejected),
+	KUNIT_CASE(dm_test_mode_valid_dblscan_rejected),
+	/* amdgpu_dm_hdmi_cec_set_edid */
+	KUNIT_CASE(dm_test_hdmi_cec_set_edid_no_notifier),
+	/* amdgpu_dm_s3_handle_hdmi_cec */
+	KUNIT_CASE(dm_test_s3_handle_hdmi_cec_suspend),
+	KUNIT_CASE(dm_test_s3_handle_hdmi_cec_resume),
 	{}
 };